Some of Microsoft's efforts to disparage open-source software such as Linux have backfired, according to a recent memo by the software maker.

Top Microsoft executives, including co-founder Bill Gates and Chief Executive Steve Ballmer, have long derided open-source software as being everything from a "cancer" to "Pac-Man-like." But those messages have failed to diminish the popularity of open-source programs such as Linux among developers and customers, according to a Microsoft memo distributed at a strategy meeting in Berlin in September.

"Messaging that discusses possible Linux patent violations, pings the OSS (open-source software) development process for lacking accountability, attempts to call out the 'viral' aspect of the GPL (General Public License), and the like are only marginally effective in driving unfavorable opinions...and in some cases backfire," the memo states.

Microsoft representatives declined to comment Wednesday on the memo, but its authenticity was confirmed by a person familiar it.

The memo, which was posted this week on Opensource.org, summarizes a project at Microsoft called "Attitudes Towards Shared Source and Open Source Research."

As part of the project, the company conducted a telephone survey of developers and other IT workers in the United States, Brazil, France, Germany, Sweden and Japan. The total size of the telephone survey was not noted, but the memo states that outside the United States "individual country and audience sample sizes are extremely small."

Among the survey's conclusions:

 "Familiarity and favorability for OSS and Linux was high across geographies and audiences."

 "Messages that criticize OSS, Linux and the GPL are NOT effective."

 "Overall respondents felt the most compelling reason to support OSS was that it 'offers a low total cost of ownership (TCO)'."

The open-source movement--exemplified by the Linux operating system and the GPL that governs it--features collaborative programming by all comers. In the case of Linux, participants include several companies that distribute Linux and also larger corporations such IBM and Intel, as well as volunteers all over the world.

With so many developers cooperating on the same project--the argument goes--the software improves faster than with proprietary programming typified by Microsoft. In addition, Linux is essentially free, although companies such as Red Hat sell a version at a modest price with the goal of earning additional revenue through installation and maintenance contracts.

According to the memo, the survey was conducted between July and September of 2001, about the same time that Microsoft executives turned up the rhetorical heat on Linux.

In May 2001, Senior Vice President Craig Mundie presented a paper in which he argued that releasing source code into the public domain is "unhealthy" and causes security risks. "As history has shown, while this type of model may have a place, it isn't successful in building a mass market and making powerful, easy-to-use software broadly accessible to consumers."

Ballmer, during an interview with the Chicago Sun-Times on June 1, said that "Linux is a cancer that attaches itself in an intellectual property sense to everything it touches."

Later that month, Gates said in an interview with CNET News.com that "if you say to people, 'Do you understand the GPL?' (then) they're pretty stunned when the Pac-Man-like nature of it is described to them."

The GPL requires that anyone be allowed to redistribute software covered by it; patent licensees such as Microsoft won't necessarily grant such rights.

Bruce Perens, co-founder of the Open Source Initiative, said Wednesday that he had no knowledge of the memo but that it "sounds like what you would expect from them."

More recently, Microsoft has appeared to soften its public stance.

"We've have initiated a shared source program. We're learning, if you will, from the Linux world," Ballmer told CNET News.com in October.